Paper and Ink Testing - Set-off

Set-off

Set-off is defined as the tendency of ink to transfer from a freshly printed surface to another paper when pressed without any friction. Set-off is an unwanted behavior of paper and ink. It is influenced by the characteristics of the paper and ink: a porous paper surface absorbs the ink fast results in lesser set-off, as do inks that dry (or set) quickly. The higher the speed of the press, the higher the set-off will be.

Set-off is measured at two different time intervals, 0.35s and 3s. A freshly printed surface is pressed against a paper after 0.35s and after 3s. Then the set-off density is measured. The idea behind selecting these two timings is to know what will be the set-off when the materials are used in a high-speed press and a low-speed press. The table below gives an example of set-off measurement.